Manufacture of flax fiber



June 2, 1931.4

E. R. CLARK MANUFAGTURE oF FLAX FIBER Filed Aug. 17, 1927 2 sheets-sheet 1 l 2 u ATTORNEYS 1 ,sosg593 June 2, 1931. E.*R.-CLARK MANUFACTURE oF' FLAX FIBER Filevd Aug. 17, 1927 Sheets-Sheet 2 Patented June 2, 1.931

UNITED STATES PATENT OFFICE.

EDGAR EA'YnoND CLARK, 0E PITTSBURGH, PENNSYLVANIA, AssIGNoa 'ro MILTON s. ERLANGEE, or NEW YORK, N. Y.

MANUFACTURE OF FIBER Application led August 17, 1927. Serial No. 213,511.

This invention relates to improvements in the manufacture of flax fiber, more particularly to improvements in the manufacture of flax fiber from seed flax straw.

Although several million acres are'planted annually to flax in the United States at present, only a fraction of one per cent of this acreage produces flax available for the production of commercial flaX fiber; the preponderance of the flax is grown for seed. There are at least tworeasons for this situationthe Wage standard in the United States, when present methods are used, al-

. most precludes competition with foreign sources of flax liber and the cultivation of flax for fiber is not-entirely consistent with the production of a high yield of good quality seed. As a result there isa large annual pro.- duction of seed flax straw w-hich has not been available for the production of a high grade flax fiber. Some of this seed flax straw is used in the manufacture of coarse yarns, some of it is used in the manufacture of a tow used in upholstering but not of a form suitable for spinning, some of it is used inthe manufacture of a pulp employed in thermal insulation, but much of it isburned as a waste product. y This invention provides an improved method of manufacturing flax fiber from seed flax straw. The invention makes it possible, for example, to manufacture from seed flax straw a flax fiber suitable for spinning high grade tow yarns or a flax liber product the equal of linen rags for the production of paper or a high gradel absorbent fiber product; at com.- mercially feasible costs. The invention, however, includes several improvements lof general utility in the manufacture of flax fiber. A The complete process of the'inventon comprises, first, a special retting operation, second, a special drying of the xetted material, third, a special towing operation, a nd, fourth, a vfurther cleaning operation adapted to the particular purpose for which the fiber is manufactured. The sequence and combination of the several particular operations which make up the complete process of the invention have several important advantages.

diagrammatically and conventionally, Aapparatus adapted for carryingout the process of the invention. In the accompanying drawings, Fig. y1 illustrates a retting' tank with as'- sociated apparatus; Fig. 1A represents a modified form ofheating meansfor use inv connection with the apparatus illustrated in Fig. 1; Fig. 2 represents an improved towin r' machine adapted for carrying out the specia towing operation of the invention;` Fig. 3A

represents a conventional cotton cardingmachine, and Fig. 3B represents a conventional flax tow-carding machine.V

.Seed flax straw is usually collected in bales. Before the straw issubjected to the improved retting operation of the present invention, such bales are opened and any seedsleftover from the threshing operation, as well as any residual chafl" and adventitious matter without fiber value, are separated from the. straw.

The straw is thenv packed inlargetanks equipped with suitable means for maintaining'circulation o f the retting liquor through the tank and through some appropriate external heating means. f The capacity of the` tank, advantageously, should be such as to make possible a straw to water ratio in the neighborhood of `from 1: 10,-to 1:12 witha moderate degree of compression.

Fig; 1 illustrates one form of apparatus which may be used for carrying out the retting operation. The apparatus there illustrated 'eomprisesa tank 4 provided With a screen 5 spaced some distance above the bottom and witha loose screen 6 adapted yto rest on top of the straw packed inthe tank.l Connections 7, 8 and 9, including circulating pump 10, Aare arranged to maintain circulation of retting liquori through the tank and through the straw packed therein. Theheatwater is circulated throug er 11 is arranged in the circulating'connections for raising the retting liquorv to and maintaining it `at vthe Adesired temperature. This heater, for example, ma bea shell and tube heater as illustrated in ig. 1 or the circulating liquor maybe heated irectly by the introduction of steam through a suitable injector 12, as illustrated .in Fig. 1A. Connection13 is provided for discharging liquor from the tank and connection 14 for supplying liquorto the tank, and a ipropriate valves are provided, as illustrate for regulating the supply, discharge and recirculation of the liquo The retting operation proper is advantageously carried out at a' temperature of about 30 C. and the circulation of the retting liquor is advantageously maintained at a rate such that the entire volume of the lliquor circulates through thetank, or through the external circuit including the heatingv means, not less `than about once per hour or better not less than about twice per hour.

he the retting tank with cold water oth before and after the retting operation proper, and yfollowin retting, the straw may, with advanlage, e drained before removal from the tan In a typical o eration, the'retting tank is packed with see flax straw and the straw is wet down with about 400 gallons of water for every 300 pounds o\fstraw. Cold water, say at a temperature of from 5 to 20 C., is used in this operation.l This reliminary wash E the tank .several times; this preliminary washing, including` the filling and draining of the tank, may take, for example, about 3 hours. In addition to thoroughly wetting the straw, this preliminary washing assists in removing loose dirt and a certain portion of carbohydrate matter.

In many cases, this preliminary washing is of material assistance in making -the resulting fiber product more easily land more effectively bleached.'n p '-Afte'r this preliminary washing, about the same quantity of water is again supplied to the retting tank and gradually raised to the temperature reciired forthe retting operation, about 30 vFermentation begins soon after this refilling of the tank and warming of its liquid contents. The desirable type of fermentation is accelerated b'y 'the preliminary removal or partial removal of "any readily -fermentable su ars. These in Afermenting give rise to aci products inhibitorqto the e retaction of the true retting bacteria.

ting liquor' vis maintained in circulation thrughthe retting tank 'and throu h the externalAvg-limiting means throughout t e operation and is thereby maintained at a substan- "tiallyA uniform temperature. This circulation of the retting liquor not only promotes uniformitybut also makes the retting operaflax straw is advantageousl rinsed in 4 tion readily amenable to control.l Usually,

the seed flax straw i'ssatisfactorily rettedl after about 45 hours of treatment at elevated temperatures. Reducing sugars usually disappear about 21 hours after the warming of the retted. liquor. During thev remainder of 'the retting' period, while the fermentation of pectin is proceeding, the acidity of the retted liquir'is advantageously maintained approximately at pH=6.0.

When the retting operation proper is comf .supplied to the retting tank. This 'wash water is circulated throu h the tank several times and is then drained rom the tank. The

retted strawvis then removed and -subjected to a suitable .drying operation.

With the improved control and uniformity provided by the improved retting` operation of this invention, the operation can be terminated, forl all practical purposes, by the clock once the appro riate period for the particular type and con, 'tion of straw handled is determined. The end point of the retting operation canbest be determined by noting the brittlenessof the woody matter of the flax. This feature` of the invention minimizes danger ofoverretting which makes for tenderness as well as danger of under- .rettin whichprevents satisfactory scutching. he retting process of this invention,

moreover, can be carried on without reference to the season of the year.

The moist or damp fiax straw from the retting operation may be dried in a variety of ways; but the ldrying is advantageously carried out at temperatures which do not at any time during the drying operation exceed about 60 C., to avoid the premature swelling of the pectinous matter of flax and its setting to a permanent stiiened form. Flax driedat too high a temperature is unsuited to the finer forms of spinning, particularly' wet spinning. By'maintainin the temperatures. during drying below t is value, the

qualit7 of the fiax fiber produced is much enhance It is also advantageous to' reduce the temperature to about 35 C. or lessas soon as the straw becomes sensibly dry to avoid any loss of moisture and oily elements necessary for suppleness. This drying can be carried out in any convenient Aform of= apparatus. v y

In carrying out the complete process of the invention, the drl retted flax is then straighten and open the fiber, to break up subjected to a specia Vtowing operation to tangles,and to separate the shives. An 'apl paratus adapted for carrying out this special towin operation is illustrated in Fig. 2.

Re erring to-Fig. `2, the flax passes first between a series of rolls 15 where it is su eration'. These breaking rolls are in thempairs of fluted breaking jected to a breaking opoperating portions of the lattices move inv selves of conventional construction and operation. From these `breaking rolls, the flax is delivered between a pair oftoothed lattices 16 and 17 by means of a traveling apron 18. A stripping'brush may be arranged as illustrated. The lower lattice 16 is carried by rotating supports 18 and 19 and the upper lattice 17 is carried by rotating supports'20 and 21. These rotating supports for the lattices 16 and 17 are arranged so that the cosubstantially parallel planes. The lattices are driven in the same direction. The teeth on the lower lattice are inclined toward the direction of motion of the latice and the teeth on the upper lattice lare inclined against the direction of motion of the lattice., The lower lattice 16 is driven at a speed suliiciently greater than that of the upper lattice 17 so that the draft in passing between the lattices exceeds the maximum fiber length. These lattices may comprise, for example, teeth mounted in slats. the slats in turn being carried at each end by sprocket chains. A dofting wheel 22, for example, a bristle or wire covered wheel', is arranged to remove ber from the lattice 16. The rotating'support 21 is advantageously arran-ged, as illustrated, so that the upper lattice 17 moves away from the lower lattice 16 before'the lower lattice leaves the plane of its travel irl-cooperation is advantageously driven at a speed such that the velocity at the periphery is somewhat greater, say 5%, than the velocity of the lattice 16. v

From the dofli'ng wheel- 22', the flax is again delivered to a series of pairs of breaking rolls 15a or to a shaking mechanism 23 adapted to subject the flax to a tossing action or the flax may be passed successively through breaking rolls and over such shaking mechanism. By means of another traveling apron l 18a, the flax may then be delivered between another pair of lattices similar to 16 and 17 and thence through'another-series of pairs of breaking .rolls similar to 15a and then over a shaking mechanism similar to-23, and so on, any desired or re uired number of times. For example, the ax, after passing through a series of pairs of preliminary breaking rolls, such as 15, may be passed three times in succession through the ap aratus illustrated between the-apron 18 an the point designated C in Fig. 1 and finally discharged l through a pair of lattices 16o and l170 similar to lattices 16 and 17. The breaking 'rolls following the dofng wheels, for example, the breaking rolls 15a following doiling wheel- 22, are advantageously driven at a speed such that the peripheralvelocity of the breaking rolls is a little greater than that of the doin wheel with which theycooperate.

The operation carried out by means of the lattices 16 and 17, and by the doingrwheel'v Aoperations for the manufacture of flax. It efis the production of a fiber stock yreadily adaptable to carding andspinning or other textiles, paper, absorbents, andthe like. The retting process of the invention is rapid and controllable and is adapted to large scale factory voperation and at the same time brings the flax to condition such that, by means of the special towing operation of the invention, a satisfactory flax fiber can be produced simply and economically. Y

In the manufacture of textiles, the flax fiber is then ready for carding in the usual way, the carding operation starting the formation of the sliver for spinning. The

'spinning can then be carried out on the usual fiax machinery.

In the manufacture of paper, the fiber from the special towing operation of the invention is advantageously processed in'a cotton card- K.ing machine for complete separation of with the upper lattice. The doiiing wheel 22 yield an easily bleachable accordance with the invention, a flax ber can be obtained which is essentially pure flax and which is substantiall the equal of unbleached linen rags' for tile manufacture of paper. This fiber product may be bleached and is then substantially the equalof bleached linen rags for the' manufacture of paper.

A conventional cotton-carding machine adapted for carrying out Asuch further clean-i ing of the improved tow of the invention is diagrammatically illustrated in Fig. 3A. It

comprises a licking-in wheel 24 by which the tow is fed'to'the carding drum 25 over which the lattice 26 moves, the lattice 26 mOYing in the same 'direction but at a slightly lower velocity than the periphery of the drum 25, and a dolling'wheel 34.

Instead of processing the fiber from the lspe-'- cial towing operation of the invention in a cotton carding machine,'it may be processed on' a flax-tow-carding machine, a conventional machine adapted to this purpose being diagrammatically illustrated in Fig. 3B.` It

comprises a pair of feed rolls 27 bywhch -A series of cooperating pairs of working rolls 29 and doiiing rolls 30 are arranged about I vthe periphery of the drum 28." The carding iis elements on the drum 28 are inclined in the direction of motion. The periphery of the carding drum 28 is driven in the same direction as the cooperating portion of the periphery of the rolls 29 and wheels 30. The card ing elements on the working rolls 29 are inclined against the direction of motion and the doling elements on the wheels 30 are inclined toward the direction of motion. yThe working rolls 29 are driven at a speed such that the peripheral velocity is somewhat less than that of the carding drum 28. The carded fiber may be removed from the carding drum by a series of dofiing wheels 31, 32 and 33; the successive dofling wheels each being arranged closer to the axis of the carding drum.

The fiber product producedl by processing on the fiax tow-carding machine is similar to that produced by processing on the cotton carding machine but of longer fiber. The operation is lessexpensive than processing on the cotton card as the latter requires that the stock be first prepared in a lap form, inthe usual way, requiring additional time and labor. however a morecomplete removal of shives, and the fiax -tow card is ordinarily used only for making spinning fiber, or grades of paper in which the complete removal of shives 1s' not essential. The flax tow card yields a fiber product better adapted to the usual bleaching andl urifying operations employed in making a sorbent fiber, than does the cotton card. Whether the final cleaning operation is carried out on a cotton-carding machine or a flax tow-carding machine, or otherwise, the

complete process-of the invention including f the special retting operation, the special towing operation and this carding, makes possible the production from seed flax straw of a fiax fiber product which is free from shives,`which is extremely clean, and which is of quality comparablev to the common grades of tow produced from flax grown for ber.

This invention also includes improvements in-apparatus for carrying out the special towing operation of the invention. The apparatus illustrated, dagranunatically and conventionally, in Fig. 2 embodies this aspect of the invention.

I claim: p l 1. In retting flax, the improvement which A comprises placing the flax in a, tank, rinsing the flax in the tank by circulating cold water therethrough and, after draining off the rinsing water, supplying fresh water to the tank and maintaining it at a uniform elevvated temperature by circulating it from the tank through an external -circuit back to the The cotton card processing effects" tank and heating it while passing through the external circuit.

2. .In-drying flax subsequent to a retting operatiomthe improvement which comprises conducting the drying at temperatures higher than ordinary field drying temperature but not exceeding C. throughout the drying operation.

3. In drying flax subsequent to a retting operation, the improvement which comprises drying the flax at an initially elevated temperature and reducing the temperature as the drying proceeds, the entire drying operation being conducted at temperatures not exceeding 60 C.

4. vIn retting flax, the improvement which comprises washing the fiax straw with cool water, removing the wash water from the flax, submerging the flax in fresh water in a closed container, uniformly heating the Water to a temperature of about 30 C., circulating the water throughout the container so as to maintain uniformity of conditions affecting the fermentation, removing the 6. The process according to claim 4 in i 'which the bath is maintained at the desired temperature by circulating it through an'l external heating means.

7. The recess according to claim 4 in which uniform conditions are maintained throughout the lbath by passing its entire volume through a suitable circulating means at least once per hour.

'8. vThe which the ath is maintained during thefermIeIntation of the pectin at an acidity of about .p 6.0.'

9. The process according to claim 4 in which the tempera-ture of the drying operationjdoes notv exceed about 35 C. after the straw has become sensibly dry.

. 10. The process according to claim 4 in which' the straw is rinsed with fresh water -after the fermentation and before drying.-

. 11. Inretting flax, the improvement which comprises maintaining the material at an acldity of about pli-6.0 during the fermentation of the pectin.-

rocess according to claim 4 in C. but not exceeding 60 C., maintaining said initial temlerature until the material is sensibly dry, en lowering the temperature and completing the dryingj at a temperature not l lower than about 35 14. In the manufacture of flax fiber where.l in said fiber is subjected to retting, drying and scutching operations, the improvement which comprises drying the retted straw at atenperature maintained between 60 C. and 3 15. In the manufacture of flax fiber wherein said fiber is subjected to retting, drying and scutching operations, the improvementl which comprises drying the flax at an initially higher temperature, said initial temperature exceeding 35 C. but not exceeding 60C., maintaining said initial temperature until the material is sensibly dry, then lowering the temperature and completing the drying (ait a temperature not lower than about In testimon whereof Iaix my si ature.

El) AR RAYMOND CL K. 

